impact harmonic balancer bolt ?
impact harmonic balancer bolt ? I am having trouble tighting the bolt on the harmonic balancer. It is a gm factory bolt.I torqued it to 37 ft lbs and I cannot get it any tighter with a breaker bar and a pipe extension. My mechanic/ tuner guy says he impacts the bolt. How do I get the balancer to not move. My compressor only goes to 90 lbs. Should I use an impact with my compressor or what? Any tips you guys have?
I impact mine. My 1/2 impact will not get it tight enough. I use a 3/4 impact. I mark the bolt with a sharpie and use a protractor to set the degree. It takes a lot to get that bolt tight enough.
Are you using a new gm bolt? If so you torque it to 37ft lb then get a giant breaker bar and turn it as close to 2/3 of a full turn more as possible. There is not final torque spec on a new stock bolt.
NEVER use an impact. You risk damaging crank threads and frankly its not needed if you know what you're doing
NEVER use an impact. You risk damaging crank threads and frankly its not needed if you know what you're doing
TECH Resident
Joined: Feb 2007
Posts: 831
Likes: 0
From: Boston, MA
Ive seen several guys impact them, along with a ton of loctite. One guy, though, lost his on the highway....
I opted to do it the right way: seat the pulley using the Hawks tool, then use the old bolt to crank it down to 240ftlbs. It was a little nerve-wracking but wasn't all that difficult (I'm no muscle head either: just had to put my body into it).
Finally, torque the new bolt to 37ft lbs, then torque to 140degrees. Easy-peasy with a good size breaker bar (I got mine at Lowes).
Did you load up on loctite and let it sit? Maybe that's why it isn't budging?
I opted to do it the right way: seat the pulley using the Hawks tool, then use the old bolt to crank it down to 240ftlbs. It was a little nerve-wracking but wasn't all that difficult (I'm no muscle head either: just had to put my body into it).
Finally, torque the new bolt to 37ft lbs, then torque to 140degrees. Easy-peasy with a good size breaker bar (I got mine at Lowes).
Did you load up on loctite and let it sit? Maybe that's why it isn't budging?
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Staging Lane
Joined: Jun 2013
Posts: 59
Likes: 1
From: Pensacola, FL
Don't use an impact. I used an ARP 12-point bolt. Torqued the old bolt to 240, removed and did the ARP bolt with 190 and ARP assembly lube. Used a 1/2 inch Kobalt torque wrench with impact hex socket (additional strength) for the old bolt and 12-point socket for the ARP bolt. This was 30,000 miles ago.
Launching!
Joined: Apr 2015
Posts: 257
Likes: 1
Impact guns are murder on thrust bearings - I wouldn't use one! It's easy to remove the starter and put a large flat blade screw driver to hold the flywheel while tightening the bolt. A flywheel locking tool works best and can be purchased on ebay for about $30.00.
Last edited by unit; Jun 2, 2016 at 03:10 PM. Reason: Add info on holding flywheel.
I took the car to a tire place today.They put it on a rack and blocked the wheels.We put it in 4th gear. He tried to impact it and could not do it. He used a breaker bar with a pipe and got it to about 100 degrees and could not get it any tighter. We used the gm bolt. He said he didn't want to try to get it any tighter because he was afraid he would break it. We didn't think that it would get any tighter.
Staging Lane
Joined: Jun 2013
Posts: 59
Likes: 1
From: Pensacola, FL
I took the car to a tire place today.They put it on a rack and blocked the wheels.We put it in 4th gear. He tried to impact it and could not do it. He used a breaker bar with a pipe and got it to about 100 degrees and could not get it any tighter. We used the gm bolt. He said he didn't want to try to get it any tighter because he was afraid he would break it. We didn't think that it would get any tighter.
Launching!
Joined: Apr 2015
Posts: 257
Likes: 1
The OEM bolt won't break at 140° but it will be very tight, which is the idea. The Torque to yield tightening method was developed to ensure bolts are properly fastened and is superior to a torque wrench in most cases. Almost every engine manufacturer uses TTY for accurate engine assembly.
It would seem the OP was unprepared to do this job and then enlisted help from persons that had no experience with an LS1 engine. Using an impact wrench on a harmonic balancer bolt on any engine does more harm than good. Now he has a bolt that's not properly tightened and is an unknown quantity.
It would seem the OP was unprepared to do this job and then enlisted help from persons that had no experience with an LS1 engine. Using an impact wrench on a harmonic balancer bolt on any engine does more harm than good. Now he has a bolt that's not properly tightened and is an unknown quantity.
